Excess Copper Imbalance in Horses: It's more common than we think

Copper (Cu) has been known to be an essential trace mineral for some time. More often, however, you will hear about zinc and how important it is for nearly every vital function within the body. Only recently we learned how closely zinc’s function is tied to copper, and for many of the chemical reactions within the body, the ratio of zinc to copper is more important than the absolute amount of either mineral alone. Zinc and copper have a complementary yet seesaw relationship within the body, competing for absorption in the gut, but working together to support metabolism.

What’s so special about Copper? It is an important catalyst in the formation of hemoglobin, the oxygen-carrying molecule, as part of the cytochrome system for cell respiration, and aiding in cellular energy release. It helps oxidize vitamin C, form collagen within cell membranes, muscles, and other connective tissues. It helps with the healing process of those tissues, aids in proper bone formation, and is found in many enzymes. Copper is responsible for the enzyme that helps transport and metabolize dietary iron, oxygen-free radical metabolism, and mild anti-inflammatory effects. Being essential in the synthesis of phospholipids, copper contributes to the integrity of the myelin sheaths which cover nerves. It also aids in the pigmentation of hair and skin, as well as the health and growth of hooves. Copper, as well as zinc, is important in converting the essential thyroid hormone T3 to T4. Like most metals, it is a conductor of electricity which helps the nervous system function and is particularly important in the production of adrenaline and controlling the levels of histamine in the body.

But, in a world where most horses (and humans) have some level of zinc deficiency, what happens to copper as a result? And how does that impact their partnership within the body?

When zinc is deficient it often leads to an abundance of copper, among other minerals, and that is what we’re here to chat about today. Copper toxicity, or more commonly, excess copper imbalance. Now, before I start talking about copper toxicity, let’s agree not go googling it because is it a more complex process than the information you will find. Many of the articles will also attempt to convince you of its rarity, however, there have been some compelling studies within the last decade suggesting that copper toxicity may occur more often than previously thought. In fact, in Northern Virginia, where I am located, I am seeing an increasing number of horses with excess copper imbalance due to zinc deficiency and exogenous, unusable sources of copper.

So, what if I told you that the horse in your barn exhibiting neurologic symptoms could be suffering from excess copper imbalance instead of EPM or Lyme disease? Or that your friend’s gelding who is nervous and explosive could have copper toxicity? Or your pony with Equine Metabolic Syndrome? Or that OTTB with chronic ulcers? How about that moody mare who has violent heat cycles? And even that 4-star event horse who gets fatigued quickly and can no longer make time? Yep. Every single one of those horses’ ailments could be what a colleague of mine has dubbed ‘Mineral Burnout’ which is caused by an excess of copper and the avalanche of side effects that result.

Copper toxicity is scarcely discussed within human medicine and it’s certainly not on the radar of most veterinarians either. Unfortunately, this means many horses will go unidentified or potentially misdiagnosed, and thus untreated. While I cannot go into detail via a blog post the ways in which we can begin to aide the body in releasing the stored excess copper, I can discuss the symptoms and some of the resulting chain of reactions to help horse owners identify whether their hooved friends are suffering from mineral burnout.

Let’s begin by talking about the main factor I see causing most excess copper imbalances. Copper pipes. Yes, we’re talking about the pipes that plumb your homes and barns. In the 1970s all new construction switched from galvanized zinc piping to copper plumbing and, until the early 2000s when PVC took over in popularity, copper remained the most common piping choice. Even in some construction projects today, contractors are continuing to use copper plumbing. That copper then leaches into the water you and your horses drink and with long term exposure can cause a dramatic increase in tissue levels. The form of copper that enters the body as a result of copper plumbing is not a bio-available source, meaning the body cannot use it to fulfill dietary needs.

So, what happens with excess unusable copper? It is stored, first in the liver until it reaches its maximum storage capacity, at which point the excess copper is stored in the tissues of the brain. Excess tissue copper can exhibit as many symptoms due to the impact of the purification and detox abilities of the liver, and because it taxes the adrenals. As a result of the liver and adrenals being compromised, all other minerals become imbalanced, resulting in dysregulation of the body’s biochemical ability to function optimally. It is important to note that while supplementing copper can contribute to mineral burnout if it is not supplemented within appropriate ratios to its other mineral co-factors, food forms can be used by the body more readily and eliminated better than exogenous sources.

Symptoms of excess copper imbalance can be displayed as soft tissue breakdown, arthritis and joint pain, anxiousness, aggression, irritable and/or explosiveness, concentration issues, hair loss, moody hormonal cycles, estrogen dominance, skin issues, fatigue, heart murmurs, reduced digestive function, ulcers, hypothyroidism, tender hooves, discoordination and/or neurologic symptoms, and even laminitis. But it is certainly not limited to only these symptoms listed.

So, how can one little mineral cause so much havoc? Nearly very ailment and injury can be traced back to a vitamin and/or mineral imbalance. For our beloved horses to thrive and maintain optimal vitality, we must keep close watch on their micronutrient requirements and that those micronutrients (vitamins and minerals) are being consumed in bio-available, appropriate ratios to one another. Otherwise the delicate balance that keeps all their organs and bodily functions operating correctly, falters. It is our responsibility as diligent horse enthusiasts, not to simply “bandage” and treat the symptom, but to dig to the root cause of the issue that is presented. In the instance of a horse who has a potential excess copper imbalance, it can be extremely hard to determine, and once discovered, mineral burnout can be a long process to correct. In my practice I begin with Hair Tissue Mineral Analysis (HTMA). If enough markers indicate reason to suspect copper toxicity, I then recommend teaming up with a trusted equine veterinarian to do more extensive testing in order to determine not only how much copper is being consumed, but how much is being excreted versus stored. This is where I cannot stress enough that it is critical for horse owners to work with a nutritionist who is educated in HTMA interpretation and the complexity of copper toxicity, as well as an equine veterinarian who is willing to do the additional testing required to accurately identify the imbalance.

If you are located within the United States and Canada, I am happy to assist you in the pursuit of your horse’s optimal vitality. Please reach out should you have any questions regarding this or other topics concerning your horse’s nutritional health.